Readers of this blog know how important it is to spend your indoor time in places with good fresh air ventilation, which equals less virus and air contaminants of all kinds. At your indoor workplace and at your home, you have some control of the amount of fresh air, but what about all the other places you go? You can choose to frequent places with good fresh air! Here are some tips:
Fresh Air Meters
Of course, the most accurate way to tell is with a Safetulator Fresh Air Meter (see Apr. 29, 2022 blog post). These devices measure carbon dioxide (CO2) in the air. This odorless gas exists in the atmosphere in a concentration of about 0.04%, but it is in our exhaled breath at levels 100 times higher! The CO2 levels in a room come to a balance point between the high CO2 levels exhaled from people and the very low CO2 level coming in with the fresh air ventilation. The balance point - the measured concentration - can tell us the amount of fresh air per person. This is exactly what we want to know, since the more fresh air coming in (and exhaust air going out), the more this air dilutes the amount of viruses and other contaminants in the air. The Safetulator meters give simple color-coded results, and if it’s “in the green” then the air is meeting the fresh air safety standards.
The Nose Knows
If you don’t have a meter, most people can detect high air contaminant levels just by the smell. Poorly-ventilated spaces include a hardware store with a smell of pesticides, and an airplane cabin with an artificial chemical smell. Strong good smells also indicate poor ventilation, as in a restaurant with strong cooking smells, and a leather store with a strong and wonderful smell of leather.
Restaurants
Restaurants can have very good or very bad fresh air, or anywhere in between. Here is how restaurant ventilation works: Every restaurant that cooks food has a large exhaust hood over the cooking equipment. The fans in this hood system exhaust a large amount of air from the kitchen, as required by the building codes. If air goes out, air must come in, and this outdoor make-up air sometimes comes in directly to the kitchen. If this is the case, it tells us nothing about the amount of fresh air in the dining area full of people. In other restaurants, most or all of the make-up air comes directly into the dining area, and then some of the dining room air goes into the kitchen to make up for the exhaust air. In this case, the dining area can have excellent fresh air. The bigger the hood, and the smaller the dining area, the better will be the fresh air.
The Chipotle chain of restaurants is an example of the second, good fresh air design. They typically have these funky big round “nozzles” blowing fresh air into the dining area, and the CO2 levels are in the green.
Urgent Care Centers
Given any type of building, some will be good, some not so good for fresh air. Urgent care centers are examples. You might think that any health care operation would have good air, but that is not the case! One of our local urgent care centers has a crowded waiting room with CO2 levels that I have never measured in the green. Another one, Convenient MD, has a discrete CO2 sensor on the waiting room wall which probably means they are continuously regulating the amount of fresh air to give more fresh air when there are more people waiting, and vice versa. I have been there a couple of times, and the CO2 was in the green or right on the edge. In addition, they have an air purifier in each room, so the overall air quality that I have measured has always been well into the green. Now that’s more like it!
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